An Incremental Variational Principle Minimizing Experimental Measurement Errors and Its Application to an Intelligent Hybrid Experimental-Numerical Method

(Case of Nonlinear Elastic-Plastic Deformation Field)

Abstract

In previous studies, for the case of linear elastic deformation field, the authors developed a hybrid experimental-numerical method based on a variational principle minimizing experimental measurement errors. In this study, for the case of nonlinear elastic-plastic deformation field, first, an incremental variational principle is derived to minimize the errors and noises associated with a full-field displacement measurement such as moire interferometry. Next, on the basis of this variational principle, an intelligent hybrid experimental-numerical method is developed for the case of nonlinear elastic-plastic deformation field. The intelligent hybrid method demonstrates automatic detection and elimination of the measurement errors and smooth visualization of stress and strain contours. Furthermore, the intelligent hybrid method automatically achieves the path independence of the T^* integral, restoring the path-dependence caused by the measurement errors. This paper provides the foundation of an intelligent measurement and visualization of displacement and stress fields in actual structural components.